Power lines for an industrial, residential, or commercial building are provided through an electrical service entrance which is generally connected to a load center with a main circuit breaker. After passing through the main circuit breaker, the power lines are connected to a bus bar. A bus bar consists of electrical conductors (i.e. metal bars), one for each voltage to be distributed to branch circuits, with features that allow individual branch circuit breakers to make an electrical connection to the bus bar. Several branch circuit breakers are then connected to a bus bar to provide power to loads. Circuit breakers are well known in the art. Examples of circuit breakers are given in U.S. Pat. Nos. 4,553,115; 4,642,726; 4,654,614; 4,887,057; 5,200,724; and 5,341,191. Typically a load center contains many branch circuit breakers that can switch power to the loads on the respective branch circuits. Loads that are common in location within a building or common in their function are typically grouped together on a branch circuit that can be switched by a single circuit breaker.
An energy meter is part of the electrical service entrance to allow for the electrical service provider to measure kWh for the purposes of billing. Users of the electricity are typically billed monthly for the previous month's electricity use. However, with the increasing number of electrical appliances and devices in a household, business, or industrial plant, it is difficult for users to know what appliances and devices are large users of electricity, thereby making it difficult to know what changes should be made to reduce electricity use. Users interested in reducing energy use would benefit from both viewing real-time energy usage, and from viewing a more detailed breakdown of energy usage to be able to identify the appliances and devices that are the most significant energy users.
An example of a load center where the individual branch circuits are monitored for the purpose of controlling remotely controllable circuit breakers is disclosed in U.S. Pat. No. 5,861,683. In this patent the branch circuits are monitored for the purpose of providing information on controlling remotely controllable circuit breakers locally using a power line carrier communication method (specifically the X10 communication protocol is used). The limitation of the power line carrier communication method is that the power information cannot be viewed in a location far removed from the building. This means that users cannot view real-time energy usage when they are away from the building using the energy. Remote access to real-time energy information at the branch circuit level would allow users to monitor power at any time of day from any location in the world. There is a need, therefore, for users to view real-time power or energy usage of individual branch circuits from a remote location, rather than only total building energy usage in time increments of a month from a fixed location.
U.S. Pat. No. 5,861,683 suggests the use of current sensors on branch circuits on the opposite side of the circuit breaker from the main power connection. A typical circuit breaker panel consists of a bus bar that distributes power to individual branch circuits. The branch circuit breakers have a wire attached connected on the opposite side of the circuit breaker from the bus bar connection. This means that connecting a current sensor to the opposite side of the circuit breaker from the bus bar means that the current sensor must be added in series with a wire, or around a wire (depending on the type of current sensor). In either case, this is a deviation in the standard installation procedure used for commonly installing branch circuit breakers, which can add awkwardness the installation procedure. The side of the circuit breakers on which the current sensors are installed does not make a difference to the function of the current monitoring, however, it does make a difference to the implementation in terms of size and cost. Embedding the current sensor in the bus bar allows for a conventional breaker can be connected to the bus bar without any difference in the installation procedure. This would allow for a lower cost and more compact solution compared to a current solution where the current sensor is on the opposite side of the circuit breaker from the bus bar. Therefore, there is need for an improved apparatus for monitoring branch circuit power or energy by integrating the branch current sensors into the power bus bar to result in a compact and low cost method for monitoring power or energy in branch circuits.
Computerized Electricity Systems Inc., assignee of U.S. Patent Application Publication No. 2009/0018706, has developed a load center that employs “smart switches” that are installed in front of conventional branch-level breakers to control electricity consumption by branch circuits. The switches include current sensors measuring the current through the breakers, and the system transmits data via the internet to offer remote monitoring possibilities. In the load center referenced on the company's website, the control functionality of the system results in a module of smart switches that occupies a substantially portion of the load center housing, leaving room for only a single-row bank of circuit breakers mounted separately from the smart switch module.
The applicant of the present application has developed a unique load center that incorporates branch circuit current sensing and remote monitoring functionality in a more compact, simplified design satisfying the needs identified above, as well as several others.